313 lines
8.6 KiB
PHP
313 lines
8.6 KiB
PHP
<?php
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/**
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* Pure-PHP ssh-agent client.
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*
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* PHP version 5
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*
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* Here are some examples of how to use this library:
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* <code>
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* <?php
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* include 'vendor/autoload.php';
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*
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* $agent = new \phpseclib\System\SSH\Agent();
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*
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* $ssh = new \phpseclib\Net\SSH2('www.domain.tld');
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* if (!$ssh->login('username', $agent)) {
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* exit('Login Failed');
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* }
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*
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* echo $ssh->exec('pwd');
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* echo $ssh->exec('ls -la');
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* ?>
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* </code>
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*
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* @category System
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* @package SSH\Agent
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* @author Jim Wigginton <terrafrost@php.net>
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* @copyright 2014 Jim Wigginton
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* @license http://www.opensource.org/licenses/mit-license.html MIT License
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* @link http://phpseclib.sourceforge.net
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* @internal See http://api.libssh.org/rfc/PROTOCOL.agent
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*/
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namespace phpseclib\System\SSH;
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use phpseclib\Crypt\RSA;
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use phpseclib\System\SSH\Agent\Identity;
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/**
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* Pure-PHP ssh-agent client identity factory
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*
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* requestIdentities() method pumps out \phpseclib\System\SSH\Agent\Identity objects
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*
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* @package SSH\Agent
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* @author Jim Wigginton <terrafrost@php.net>
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* @access public
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*/
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class Agent
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{
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/**#@+
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* Message numbers
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*
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* @access private
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*/
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// to request SSH1 keys you have to use SSH_AGENTC_REQUEST_RSA_IDENTITIES (1)
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const SSH_AGENTC_REQUEST_IDENTITIES = 11;
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// this is the SSH2 response; the SSH1 response is SSH_AGENT_RSA_IDENTITIES_ANSWER (2).
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const SSH_AGENT_IDENTITIES_ANSWER = 12;
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// the SSH1 request is SSH_AGENTC_RSA_CHALLENGE (3)
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const SSH_AGENTC_SIGN_REQUEST = 13;
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// the SSH1 response is SSH_AGENT_RSA_RESPONSE (4)
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const SSH_AGENT_SIGN_RESPONSE = 14;
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/**#@-*/
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/**@+
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* Agent forwarding status
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*
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* @access private
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*/
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// no forwarding requested and not active
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const FORWARD_NONE = 0;
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// request agent forwarding when opportune
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const FORWARD_REQUEST = 1;
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// forwarding has been request and is active
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const FORWARD_ACTIVE = 2;
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/**#@-*/
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/**
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* Unused
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*/
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const SSH_AGENT_FAILURE = 5;
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/**
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* Socket Resource
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*
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* @var resource
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* @access private
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*/
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var $fsock;
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/**
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* Agent forwarding status
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*
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* @access private
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*/
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var $forward_status = self::FORWARD_NONE;
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/**
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* Buffer for accumulating forwarded authentication
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* agent data arriving on SSH data channel destined
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* for agent unix socket
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*
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* @access private
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*/
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var $socket_buffer = '';
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/**
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* Tracking the number of bytes we are expecting
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* to arrive for the agent socket on the SSH data
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* channel
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*/
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var $expected_bytes = 0;
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/**
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* Default Constructor
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*
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* @return \phpseclib\System\SSH\Agent
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* @access public
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*/
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function __construct($address = null)
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{
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if (!$address) {
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switch (true) {
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case isset($_SERVER['SSH_AUTH_SOCK']):
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$address = $_SERVER['SSH_AUTH_SOCK'];
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break;
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case isset($_ENV['SSH_AUTH_SOCK']):
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$address = $_ENV['SSH_AUTH_SOCK'];
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break;
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default:
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user_error('SSH_AUTH_SOCK not found');
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return false;
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}
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}
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$this->fsock = fsockopen('unix://' . $address, 0, $errno, $errstr);
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if (!$this->fsock) {
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user_error("Unable to connect to ssh-agent (Error $errno: $errstr)");
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}
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}
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/**
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* Request Identities
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*
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* See "2.5.2 Requesting a list of protocol 2 keys"
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* Returns an array containing zero or more \phpseclib\System\SSH\Agent\Identity objects
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*
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* @return array
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* @access public
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*/
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function requestIdentities()
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{
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if (!$this->fsock) {
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return array();
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}
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$packet = pack('NC', 1, self::SSH_AGENTC_REQUEST_IDENTITIES);
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if (strlen($packet) != fputs($this->fsock, $packet)) {
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user_error('Connection closed while requesting identities');
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return array();
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}
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$length = current(unpack('N', fread($this->fsock, 4)));
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$type = ord(fread($this->fsock, 1));
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if ($type != self::SSH_AGENT_IDENTITIES_ANSWER) {
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user_error('Unable to request identities');
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return array();
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}
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$identities = array();
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$keyCount = current(unpack('N', fread($this->fsock, 4)));
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for ($i = 0; $i < $keyCount; $i++) {
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$length = current(unpack('N', fread($this->fsock, 4)));
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$key_blob = fread($this->fsock, $length);
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$key_str = 'ssh-rsa ' . base64_encode($key_blob);
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$length = current(unpack('N', fread($this->fsock, 4)));
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if ($length) {
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$key_str.= ' ' . fread($this->fsock, $length);
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}
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$length = current(unpack('N', substr($key_blob, 0, 4)));
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$key_type = substr($key_blob, 4, $length);
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switch ($key_type) {
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case 'ssh-rsa':
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$key = new RSA();
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$key->loadKey($key_str);
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break;
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case 'ssh-dss':
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// not currently supported
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break;
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}
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// resources are passed by reference by default
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if (isset($key)) {
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$identity = new Identity($this->fsock);
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$identity->setPublicKey($key);
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$identity->setPublicKeyBlob($key_blob);
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$identities[] = $identity;
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unset($key);
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}
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}
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return $identities;
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}
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/**
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* Signal that agent forwarding should
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* be requested when a channel is opened
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*
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* @param Net_SSH2 $ssh
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* @return bool
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* @access public
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*/
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function startSSHForwarding($ssh)
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{
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if ($this->forward_status == self::FORWARD_NONE) {
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$this->forward_status = self::FORWARD_REQUEST;
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}
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}
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/**
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* Request agent forwarding of remote server
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*
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* @param Net_SSH2 $ssh
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* @return bool
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* @access private
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*/
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function _request_forwarding($ssh)
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{
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$request_channel = $ssh->_get_open_channel();
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if ($request_channel === false) {
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return false;
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}
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$packet = pack(
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'CNNa*C',
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NET_SSH2_MSG_CHANNEL_REQUEST,
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$ssh->server_channels[$request_channel],
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strlen('auth-agent-req@openssh.com'),
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'auth-agent-req@openssh.com',
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1
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);
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$ssh->channel_status[$request_channel] = NET_SSH2_MSG_CHANNEL_REQUEST;
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if (!$ssh->_send_binary_packet($packet)) {
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return false;
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}
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$response = $ssh->_get_channel_packet($request_channel);
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if ($response === false) {
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return false;
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}
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$ssh->channel_status[$request_channel] = NET_SSH2_MSG_CHANNEL_OPEN;
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$this->forward_status = self::FORWARD_ACTIVE;
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return true;
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}
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/**
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* On successful channel open
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*
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* This method is called upon successful channel
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* open to give the SSH Agent an opportunity
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* to take further action. i.e. request agent forwarding
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*
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* @param Net_SSH2 $ssh
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* @access private
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*/
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function _on_channel_open($ssh)
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{
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if ($this->forward_status == self::FORWARD_REQUEST) {
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$this->_request_forwarding($ssh);
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}
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}
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/**
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* Forward data to SSH Agent and return data reply
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*
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* @param string $data
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* @return data from SSH Agent
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* @access private
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*/
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function _forward_data($data)
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{
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if ($this->expected_bytes > 0) {
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$this->socket_buffer.= $data;
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$this->expected_bytes -= strlen($data);
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} else {
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$agent_data_bytes = current(unpack('N', $data));
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$current_data_bytes = strlen($data);
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$this->socket_buffer = $data;
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if ($current_data_bytes != $agent_data_bytes + 4) {
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$this->expected_bytes = ($agent_data_bytes + 4) - $current_data_bytes;
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return false;
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}
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}
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if (strlen($this->socket_buffer) != fwrite($this->fsock, $this->socket_buffer)) {
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user_error('Connection closed attempting to forward data to SSH agent');
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}
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$this->socket_buffer = '';
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$this->expected_bytes = 0;
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$agent_reply_bytes = current(unpack('N', fread($this->fsock, 4)));
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$agent_reply_data = fread($this->fsock, $agent_reply_bytes);
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$agent_reply_data = current(unpack('a*', $agent_reply_data));
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return pack('Na*', $agent_reply_bytes, $agent_reply_data);
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}
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}
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